1. Choe, Whittington, Lauria (1996) Valuation study in Davao, Philippines Objectives? Valuation techniques applied?

2. Objective: estimate the economic value that residents place on improving water quality in rivers and sea near their community, in particular for recreational use Apply two nonmarket valuation techniques –Stated-preference: CVM –Revealed-preference: travel-cost method Reactions?

3. Water quality in Davao What’s the status? What’s the major source of pollution? What are the consequences?

4. Davao: second largest municipality in Philippines (1990 population: 850,000) –Most densely populated portion: on coast Since mid-1980s, most households have installed flush or pour-flush toilets, voluntarily –But: toilets empty into holding tanks, which seep into ground or overflow into street drains and ditches –< 1% of households are connected to sewer lines Consequence: Davao River and Davao Bay have become highly polluted –What had been most popular beach, Times Beach, has gotten little use since 1992 public health warnings

5. Water improvement scenarios Scenario 1: Water Quality Improvement Plan Scenario 2: Sewer Plus Treatment Plan What’s the difference?

6. Water improvement scenarios Scenario 1: Water Quality Improvement Plan –Assume there is a city-wide plan to clean up rivers and sea and make Times Beach safe for swimming and other recreation Did not specify what plan would entail –If adopted, each household will be required to pay a monthly fee –Sample: half of households that owned homes with water-sealed toilets; all other households

7. Scenario 2: Sewer Plus Treatment Plan –Assume there is a city-wide plan to construct sewer lines and treatment plants, which will not only clean up rivers and sea and make Times Beach safe for swimming and other recreation, but will also enhance public health –If adopted, each household will be required to pay a monthly fee –Sample: other half of households that owned homes with water-sealed toilets

8. Types of values studied DavaoUse values: make Times Beach safe for recreational use, improved sanitation services Developing countriesUse values: initially, mainly water supply, sanitation, and recreation; more recently, air and water quality, health, biodiversity (inc. passive use) Developed countriesMainly passive use values of natural areas

9. Choice of monetary measure of welfare change DavaoWTP for beach cleanup (Scenario 1) WTP for improved sanitation service (Scenario 2) Developing countriesUsually as above: WTP Developed countriesUsually WTP (compensating surplus, if welfare gain; equivalent surplus, if welfare loss) Sometimes WTA (e.g., for loss of protected area) But often get protest bids

10. Field procedures: Davao What were the steps in conducting the study?

11. 1.Conduct focus groups with small number of households, to learn about existing situation and design initial version of questionnaire 2.Pre-test questionnaire with larger number of households 3.Finalize questionnaire and translate into Tagalog 4.Design sampling procedure (2-stage stratified random sample of 1200 households) 5.Train enumerators (role playing, practice interviews) 6.Conduct survey through face-to-face interviews 7.Confirm that enumerators completed interviews, and check completed questionnaires 8.Conduct followup interviews if information missing or seemingly in error About half a year, from start to finish

12. Field procedures Developing countriesSame as in Davao Developed countriesSimilar to Davao, but:  Usually no need to translate questionnaire into foreign language  More information is typically available for designing the sampling frame (in Davao, 32 percent of households could not be located)  Surveys are usually conducted via telephone or mail instead of face-to-face

13. Description of hypothetical good How did they describe the scenarios to the respondents?

14. Description of hypothetical good DavaoRead description from prepared text Show diagrams and pictures Developing countriesSimilar Developed countriesOften more detailed description and more props: goods often less familiar, payment mechanism often less direct

15. Bid elicitation procedure What procedure did they use to elicit respondents’ WTP?

16. Bid elicitation procedure DavaoTwo-step bidding game with random starting point (25, 50, 100, 150, 200 pesos) and open-ended final bid Developing countriesVarious:  Sometimes as above  Usually just open-ended question (worse)  Sometimes referendum (“take-it-or-leave-it”) approach (better): randomly allocate a set of “prices” across respondents, each of whom “votes” yes or no in view of the price he or she was allocated Developed countriesReferendum approach endorsed by NOAA panel and strongly favored in U.S.

17. Information generated by bid elicitation procedure 1.Open-ended question: yields point estimate of household’s WTP –WTP = WTP open-ended –Analyze using OLS

18. Information generated by bid elicitation procedure 1.Open-ended question: yields point estimate of household’s WTP –WTP = WTP open-ended –Analyze using OLS 2.“Yes/No” questions: classify household’s WTP into three categories –Category 1: WTP < L Category 2:L  WTP < H Category 3:H  WTP –Analyze using more sophisticated econometric methods (e.g., probit)

19. Testing the accuracy of bids What did they do?

20. 1.Cooperativeness of respondents –Only 3% of households refused to be interviewed 2.Plausibility of bids, cf. current income and expenditures –Median bids = ~$1/month –Mean water bill = ~$5/month; mean income = ~$180/month 3.Explanatory power of model of determinants of WTP bids 4.Consistency of model results with economic theory 5.Neutrality of survey design –Does starting value of iterative bidding affect final bids? 6.Split-sample “scope” test –Do households that own houses with water-sealed toilets bid more in Scenario 2 than in Scenario 1? Same approaches are used in other contingent valuation studies

24. Policy implications What do they conclude about viability of investments in improved sanitation services?

25. Policy implications What do they conclude about viability of investments in improved sanitation services? –Not viable! So, should municipal/national government proceed with investments in sewerage system?

26. Policy applications DavaoDetermine which investments in improved sanitation services, if any, are viable Conclusion: not much is viable at present Developing countriesSimilar to above, including for water supply Set entrance fees for parks Developed countriesDecide how to use public lands (e.g., harvest timber or protect?) Determine whether public should purchase private lands to protect them Determine compensation for environmental damage (Exxon Valdez)